The other day I was listening to Carl Sagan's Essay audio book and he was discussing the fact that it took few centuries for us humans, to remove ourselves from the center of the Solar system and put the Sun where it belongs.

While I was listening to the audio book and to all of the arguments and facts that Carl Sagan was presenting, I was wondering where did we go, after we removed ourselves out from the center of the Solar System. We can't just float around randomly in space (hmm, aren't we doing exactly that?). We should have positioned us somewhere else, preferably more important place than the center of the Solar System. More...

I am about to disappoint you. It is that simple. Time machine was never invented.

What I imply, when I use the word ‘time travel’ is to be able to move back and forth in time, somewhat similar to the way we move in space. In other words you pick up the time-travel bus and instead of arriving at work, you arrive yesterday or tomorrow (could be at work, no problem of course, for this discussion we are not interested in the space aspects of your adventure).

In school, when studying special and general relativity theory, people usually use the so called ‘twin paradox’ to give an example of ‘time travel’ in the future. This is more like a one way ticket to the future for a near-light speed traveler. The interesting question is how you manage to travel both directions – to the future and to the past. More...